Waterproof microphone

Abstract

The utility model provides a waterproof microphone, including substrate, with the shell of the cavity that surrounds of substrate is received and the MEMS chip that is received in the cavity, substrate is provided with first cavity, the first sound hole of intercommunication outside and first cavity, and the second sound hole of intercommunication first cavity and the cavity, first sound hole and second sound hole are mutually staggered in the thickness direction of substrate, the side of substrate is close to the shell is provided with waterproof membrane, and waterproof membrane is clamped between MEMS chip and substrate and covers second sound hole, the utility model provides a waterproof microphone through design first cavity and staggered first sound hole and second sound hole, lengthen waterproof membrane and the distance of first sound hole, the pressure that the waterproof membrane received is buffered, improve waterproof function of waterproof membrane.

Description

[Technical Field]

[0001] This utility model relates to the field of sensor design, and more specifically, to a waterproof microphone. [Background Technology]

[0002] With the development of electronic technology, microphones are widely used in electronic products such as mobile phones and laptops, especially MEMS (Micro-Electro-Mechanical System) microphones, which have a smaller package size than traditional electret microphones and are more widely used. MEMS microphones have certain requirements for waterproofing in practical applications; water ingress can damage the functionality of electrical devices or even directly destroy them.

[0003] Existing MEMS microphones have a waterproof membrane directly attached to the sound hole. However, this structure has certain problems. During waterproof testing, it was found that water pressure can directly reach the waterproof membrane through the microphone sound hole. Since the waterproof membrane has no other structure to support it, it is easily deformed under pressure, causing the waterproof membrane to fail. This allows water and other liquids to pass through the waterproof membrane and enter the MEMS chip, resulting in product malfunction and failure to achieve the waterproof effect.

[0004] Therefore, it is necessary to provide a new waterproof microphone to solve the above-mentioned technical problems. [Utility Model Content]

[0005] In view of the above problems, the purpose of this utility model is to provide a waterproof microphone to solve the problem of poor waterproof performance of traditional MEMS microphones.

[0006] The waterproof microphone provided by this utility model includes a substrate, a shell forming a receiving cavity with the substrate, and a MEMS chip housed in the receiving cavity. The substrate is provided with a first cavity, a first sound hole communicating with the outside and the first cavity, and a second sound hole communicating with the first cavity and the receiving cavity. The first sound hole and the second sound hole are offset from each other in the thickness direction of the substrate. A waterproof membrane is provided on the side of the substrate near the shell. The waterproof membrane is sandwiched between the MEMS chip and the substrate and covers the second sound hole.

[0007] Preferably, the substrate includes a first substrate and a second substrate stacked along the thickness direction of the substrate, the first substrate having the first acoustic hole, the second substrate having the second acoustic hole, and the first cavity being formed between the first substrate and the second substrate.

[0008] Preferably, a first sink groove is provided on the side of the first substrate near the second substrate, and a second sink groove corresponding to the first sink groove is provided on the side of the second substrate near the first substrate. The first sink groove and the second sink groove together enclose the first cavity.

[0009] Preferably, a groove is provided on the side of the substrate near the waterproof membrane, and the second acoustic hole is disposed in the groove. The waterproof membrane and the groove together form a second cavity, and the second cavity communicates with the first cavity through the second acoustic hole.

[0010] Preferably, the height of the first cavity along the thickness direction of the substrate is H1, the height of the second cavity along the thickness direction of the substrate is H2, and the ratio of H1 to H2 is greater than 2:1.

[0011] Preferably, the waterproof membrane includes a support portion fixed to the substrate and a waterproof and breathable portion fixed to the support portion. The support portion is bonded and fixed to the substrate by an adhesive, and the waterproof and breathable portion covers the second acoustic hole.

[0012] Preferably, the waterproof and breathable part is made of one of polytetrafluoroethylene, expanded polytetrafluoroethylene, polyimide, and polyurethane, and the thickness of the waterproof and breathable part ranges from 2 to 75 μm.

[0013] Preferably, the support portion includes a first channel extending through the thickness direction of the substrate, and the waterproof and breathable portion is attached to the side surface of the support portion near the MEMS chip and covers the first channel, wherein the opening of the first channel is larger than the opening of the groove.

[0014] Preferably, both the first acoustic hole and the second acoustic hole are circular, the diameter of the first acoustic hole is greater than the diameter of the second acoustic hole, and the number of the second acoustic holes is not less than the number of the first acoustic holes. In the thickness direction of the substrate, the projections of the first acoustic hole and the second acoustic hole do not coincide.

[0015] Preferably, the device further includes an ASIC chip housed within the housing cavity, the substrate being a circuit board, and the ASIC chip being electrically connected to the MEMS chip and the substrate via gold wires.

[0016] The beneficial effects of this utility model are as follows:

[0017] By setting a first cavity, a first acoustic hole connecting the outside to the first cavity, and a second acoustic hole connecting the first cavity to the receiving cavity on the substrate, the first and second acoustic holes are staggered in the thickness direction of the substrate. A waterproof membrane is set on the side of the substrate near the outer shell, sandwiched between the MEMS chip and the substrate and covering the second acoustic hole. The waterproof membrane is attached to the second acoustic hole, and the first cavity between the first and second acoustic holes is designed to increase the distance between the waterproof membrane and the first acoustic hole. This allows water pressure to undergo multiple buffering processes when it reaches the waterproof membrane, reducing the water pressure on the waterproof membrane and protecting it. At the same time, the staggered setting of the first and second acoustic holes allows water pressure to directly reach the first acoustic hole and be buffered by the first cavity, reducing the water pressure reaching the second acoustic hole and thus reducing the water pressure reaching the waterproof membrane, thereby improving the waterproof function of the waterproof membrane. [Attached Image Description]

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A cross-sectional view of the waterproof microphone provided by this utility model;

[0020] Figure 2 for Figure 1 Enlarged view of region A in the middle;

[0021] Figure 3 A schematic diagram of the second substrate provided by this utility model;

[0022] Figure 4 A schematic diagram of the first substrate provided by this utility model.

[0023] In the picture:

[0024] Waterproof microphone 100, housing 1, receiving cavity 11, first cavity 12, second cavity 13, first substrate 2, first sound hole 21, first recess 22, second substrate 3, second sound hole 31, second recess 32, groove 33, waterproof membrane 4, support part 41, waterproof and breathable part 42, MEMS chip 5, ASIC chip 6, gold wire 7. 【Detailed Implementation Methods】

[0025] To describe the structure of the waterproof microphone of this utility model in detail, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0026] Figure 1According to the main view cross-sectional structure of the waterproof microphone 100 provided by this utility model, based on Figure 1 As shown, the waterproof microphone 100 provided by this utility model includes a substrate, a shell 1 that forms a receiving cavity 11 with the substrate, and a MEMS chip 5 housed in the receiving cavity 11. The substrate is provided with a first cavity 12, a first sound hole 21 that connects the outside to the first cavity 12, and a second sound hole 31 that connects the first cavity 12 and the receiving cavity 11. The first sound hole 21 and the second sound hole 31 are offset from each other in the thickness direction of the substrate. A waterproof membrane 4 is provided on the side of the substrate near the shell 1. The waterproof membrane 4 is sandwiched between the MEMS chip 5 and the substrate and covers the second sound hole 31.

[0027] In this embodiment, when the waterproof microphone 100 is in use, external sound enters the first cavity 12 through the first sound hole 21 to input a vibration signal or pressure signal into the first cavity 12, and then is transmitted to the waterproof membrane 4 through the second sound hole 31. The waterproof membrane 4 is excited by the vibration signal or pressure signal and vibrates, which is transmitted to the inside of the MEMS chip 5. The MEMS chip 5 converts the sensed information into a detectable electrical signal and transmits it to external electronic devices.

[0028] The waterproof membrane 4 also serves to prevent dust and liquids from the external environment from entering the internal cavity of the MEMS chip 5. This helps maintain a clean and tidy internal environment for the MEMS chip 5, thereby ensuring that the MEMS chip 5 can quickly and accurately sense sound pressure and convert it into an electrical signal. By attaching the waterproof membrane 4 to the second sound hole 31 and designing the first cavity 12 between the first sound hole 21 and the second sound hole 31, the distance between the waterproof membrane 4 and the first sound hole 21 is increased. This allows external water to undergo multiple buffering processes when it reaches the waterproof membrane 4, reducing the water pressure on the waterproof membrane 4 and protecting it.

[0029] Furthermore, the first sound hole 21 and the second sound hole 31 are staggered. By staggering the first sound hole 21 and the second sound hole 31, the water pressure is buffered by the first cavity 12 after reaching the first sound hole 21, thereby reducing the water pressure reaching the second sound hole 31 and thus reducing the water pressure reaching the waterproof membrane 4, thereby improving the waterproof function of the waterproof membrane 4.

[0030] Furthermore, in this embodiment, the substrate includes a first substrate 2 and a second substrate 3 stacked along the thickness direction of the substrate. The first substrate 2 has a first acoustic hole 21. The second substrate 3 has a second acoustic hole 31, and a first cavity 12 for sound transmission is formed between the first substrate 2 and the second substrate 3.

[0031] A first recess 22 is provided on the side of the first substrate 2 closest to the second substrate 3, and a second recess 32 corresponding to the first recess 22 is provided on the side of the second substrate 3 closest to the first substrate 2. The first recess 22 and the second recess 32 together enclose a first cavity 12. The first cavity 12 is formed by the two substrates, which can ensure the structural stability of the substrates.

[0032] Furthermore, a groove 33 is provided on the side of the substrate near the waterproof membrane 4, and a second acoustic hole 31 is disposed in the groove 33. The waterproof membrane 4 and the groove 33 together form a second cavity 13, which is connected to the first cavity 12 through the second acoustic hole 31. The second cavity 13 can further disperse the pressure of the water entering through the second acoustic hole 31, thus protecting the waterproof membrane 4.

[0033] The height of the first cavity 12 along the thickness direction of the substrate is H1, and the height of the second cavity 13 along the thickness direction of the substrate is H2. The ratio of H1 to H2 is greater than 2:1. For example, the ratio of H1 to H2 can be 3:1, 4:1, or 5:1. Within this range, the space of the first cavity 12 and the second cavity 13 can be reasonably allocated. The larger H1 can meet the microphone's requirements for low-frequency response space, while the smaller H2 can achieve its function without occupying too much space and can ensure the structural strength of the second substrate and buffer the pressure on the waterproof membrane 4.

[0034] In this embodiment, the waterproof membrane 4 includes a support portion 41 fixed to the substrate and a waterproof and breathable portion 42 fixed to the support portion 41. The support portion 41 is bonded to the top surface of the substrate by an adhesive, and the waterproof and breathable portion 42 covers the second acoustic hole 31. More specifically, the waterproof and breathable portion 42 is bonded to the top surface of the support portion 41 by an adhesive. Optionally, the waterproof and breathable portion 42 is made of one of polytetrafluoroethylene, expanded polytetrafluoroethylene, polyimide, or polyurethane. The microporous structure of the waterproof and breathable portion 42 made of the above materials can block various particles while allowing air to pass through, thus having a high-performance filtration function and good waterproof and breathable effect. Furthermore, the thickness of the waterproof and breathable portion 42 is in the range of 2-75 μm. Setting the thickness of the waterproof and breathable portion 42 within this range ensures good waterproof performance without increasing acoustic impedance and reducing signal strength.

[0035] The support portion 41 of the waterproof membrane 4 can distribute the pressure on the waterproof and breathable portion 42 to the substrate, thus extending the service life of the waterproof and breathable portion 42. Furthermore, the support portion 41 is fixed to the top surface of the substrate by the adhesive, which improves the stability of the waterproof membrane 4 and the substrate and can achieve a sealing connection, thereby enabling the waterproof membrane 4 to better perform the functions of filtration and isolation.

[0036] In this embodiment, the support portion 41 includes a first channel extending through the thickness direction of the substrate. The waterproof and breathable portion 42 is attached to the side surface of the support portion near the MEMS chip 5 and covers the first channel. The opening of the first channel is larger than the opening of the groove 33. By setting the opening of the first channel of the support portion 41 to be larger than the opening of the groove 33, the area of ​​the waterproof and breathable portion 42 exposed in the second cavity 13 is increased, thereby improving the signal-to-noise ratio of the microphone.

[0037] Optionally, the first sound hole 21 and the second sound hole 31 can be circular, square, or irregular in shape. In this embodiment, both the first sound hole 21 and the second sound hole 31 are circular. Circular sound holes allow sound waves to enter the microphone more uniformly, reducing edge reflections and standing wave effects. The diameter of the first sound hole 21 is larger than the diameter of the second sound hole 31. The number of second sound holes 31 can be the same as the number of first sound holes 21, or the number of second sound holes 31 can be greater than the number of first sound holes 21. In this embodiment, there is one first sound hole 21 and four second sound holes 31. The projections of the first sound hole 21 and the second sound hole 31 do not coincide in the thickness direction of the substrate. By setting the diameter of the first sound hole 21 to be larger than the diameter of the second sound hole 31, the larger diameter of the first sound hole 21 allows more sound waves to enter, while the smaller diameter and greater number of second sound holes 31 reduce standing waves and reflections of sound waves within the first cavity 12, resulting in a more uniform sound pressure distribution and reduced distortion.

[0038] Furthermore, in this embodiment, an ASIC chip 6 is also included, housed within the receiving cavity 11. The substrate is a circuit board, and the ASIC chip 6 is electrically connected to the MEMS chip 5 and the substrate via gold wires 7. The MEMS chip 5 can receive sound from the outside world and convert it into an electrical signal. The ASIC chip 6 receives the electrical signal emitted by the MEMS chip 5, processes the electrical signal, and outputs it externally. The MEMS chip 5 and the ASIC chip 6 are electrically connected via gold wires 7, allowing the signal output by the MEMS chip 5 to be processed by the ASIC chip 6. The ASIC chip 6 is electrically connected to the substrate via gold wires 7, allowing the electrical signal output by the MEMS chip 5 to be processed by the ASIC chip 6 and then output externally.

[0039] The above are merely embodiments of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.

Claims

1. A waterproof microphone, comprising a substrate, a housing forming a receiving cavity with the substrate, and a MEMS chip housed within the receiving cavity, characterized in that, The substrate is provided with a first cavity, a first acoustic hole communicating with the outside and the first cavity, and a second acoustic hole communicating with the first cavity and the receiving cavity. The first acoustic hole and the second acoustic hole are offset from each other in the thickness direction of the substrate. A waterproof membrane is provided on the side of the substrate near the outer casing. The waterproof membrane is sandwiched between the MEMS chip and the substrate and covers the second acoustic hole.

2. The waterproof microphone according to claim 1, characterized in that, The substrate includes a first substrate and a second substrate stacked along the thickness direction of the substrate. The first substrate has the first acoustic hole, the second substrate has the second acoustic hole, and the first cavity is formed between the first substrate and the second substrate.

3. The waterproof microphone according to claim 2, characterized in that, A first sink groove is provided on the side of the first substrate near the second substrate, and a second sink groove corresponding to the first sink groove is provided on the side of the second substrate near the first substrate. The first sink groove and the second sink groove together enclose the first cavity.

4. The waterproof microphone according to claim 1, characterized in that, A groove is provided on the side of the substrate near the waterproof membrane, and the second acoustic hole is provided in the groove. The waterproof membrane and the groove together form a second cavity, and the second cavity communicates with the first cavity through the second acoustic hole.

5. The waterproof microphone according to claim 4, characterized in that, The height of the first cavity along the thickness direction of the substrate is H1, and the height of the second cavity along the thickness direction of the substrate is H2, with the ratio of H1 to H2 being greater than 2:

1.

6. The waterproof microphone according to claim 4, characterized in that, The waterproof membrane includes a support portion fixed to the substrate and a waterproof and breathable portion fixed to the support portion. The support portion is bonded and fixed to the substrate by an adhesive, and the waterproof and breathable portion covers the second acoustic hole.

7. The waterproof microphone according to claim 6, characterized in that, The waterproof and breathable part is made of one of the following materials: polytetrafluoroethylene, expanded polytetrafluoroethylene, polyimide, and polyurethane, and the thickness of the waterproof and breathable part ranges from 2 to 75 μm.

8. The waterproof microphone according to claim 6, characterized in that, The support portion includes a first channel extending through the thickness direction of the substrate. The waterproof and breathable portion is attached to the side surface of the support portion near the MEMS chip and covers the first channel. The opening of the first channel is larger than the opening of the groove.

9. The waterproof microphone according to claim 1, characterized in that, Both the first and second acoustic holes are circular. The diameter of the first acoustic hole is larger than the diameter of the second acoustic hole, and the number of the second acoustic holes is not less than the number of the first acoustic holes. In the thickness direction of the substrate, the projections of the first and second acoustic holes do not coincide.

10. The waterproof microphone according to claim 1, characterized in that, It also includes an ASIC chip housed within the housing cavity, the substrate being a circuit board, and the ASIC chip being electrically connected to the MEMS chip and the substrate via gold wires.

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